Photographic developer containing a pyridine derivative

ABSTRACT

The invention provides a developer solution for simultaneously developing and toning positive photographic prints, the solution containing hydroquinone as the developer and a specified pyridine derivative as toning agent to provide a brown-tinted (e.g. yellowish-brown, olive-brown, reddish-brown, or neutral-brown) print.

United States Patent PHOTOGRAPHIC DEVELOPER CONTAINING A PYRIDINEDERIVATIVE 3 Claims, No Drawings US. Cl. 96/52, 96/66 Int. Cl G034:7/00, G03c 5/30 Field of Search 96/52, 66, 66.3

[56] References Cited UNITED STATES PATENTS 2,875,050 2/1959Goldbergetal. 96/663 FOREIGN PATENTS 494,468 10/1938 Great Britain 96/52Primary Examiner-Norman G. Torchin Assistant Examiner-Mary F. KelleyAttorney-Fleit, Gipple & Jacobson ABSTRACT: The invention provides adeveloper solution for simultaneously developing and toning positivephotographic prints, the solution containing hydroquinone as thedeveloper and a specified pyridine derivative as toning agent to providea brown-tinted (e.g. yellowish-brown, olive-brown, reddishbrown, orneutral-brown) print.

PHOTOGRAPHIC DEVELOPER CONTAINING A PYRIDINE DERIVATIVE This inventionrelates to photographic developers for obtaining color-toned prints.

It has long been known to tone positive prints by sulfur toning, bymetal salt toning with, for example, gold, copper or vanadium salts, orby chromogenous development of the print (E. Mutter: Kompendium derPhotographie, Vol. III pages 104-113, Verlag fur Radio-Foto-Kinotechnik,Berlin-Borsigwalde, 1963).

However, these methods suffer from substantial disadvantages due, on theone hand, to the complexity of the method concemed-a number ofadditional working operations are required for developing and oftenfurther operations for bleaching and toning, and on the other hand,tothe often unsatisfactory quality of the toned print. In particular thetoning often has an unfavorable effect on the grain size of the blacksilver print and brown-tinted images become clayyellow, especially whenusing a sulfur toner. Also over exposed and underdeveloped prints tendto become too bright and deadened pictures take on a blackish tone. Inaddition, with chromogenous developers the solutions are not stable instorage and must therefore, be mixed from two separate containers beforebeing used.

It has also been proposed to achieve a brownish coloration of the printby use of very dilute solutions of hydroquinone (Mutter, Vol. III, pages79 and 80). Using this method, how ever, from the exposure time isincreased by a factor of from 1.5-7 and also extended developer timesare necessary. This provides prints with no contrast and in which thebrown tone is hardly detectable. In using some of these developers it isproposed that beige-colored papers should be used, in which not thesilver print but the whole surface of the paper is colored.

The present invention has for its aim to provide a developer solutionwhich permits development and toning of the positive print in oneworking operation without extended exposure or developing times, whilemaintaining as small a grain size and providing toning of the print,particularly in a neutral-brown coloration.

Surprisingly it has been found that these requirements can be met ifthere is added to an alkaline hydroquinone-type developer solution,optionally containing a superadditive, such as phenidon, a pyridinecompound of the formula:

where R,, R R and R each represent a hydrogen atom. a

C C, alkyl group, or a hydroxyalkyl, aminoalkyl, or alkoxyal- Usingthese pyridine additives yellowish-brown, olivebrown, reddish-brown orneutral-brown prints can be obtained depending on the particularadditive used.

An advantage of the toning agents used in accordance with the presentinvention is the fact that they can be added directly to the developersolution, e.g. of the hydroquinone/Metol type, and that development andtoning can be achieved in one working operation. Known superadditives,e.g. l-phenyl-pyrazolone or l-phenyl-Il-amino pyrazolone, can also beadded to the developer solution, if desired.

A further advantage of the toning agents used in accordance with theinvention lies in the fact that the grain size of the silver print isnot unfavorably influenced.

Finally, a further advantage lies in the fact that the exposure and alsothe developing times do not need to be extended.

The novel toning developers of the invention can be used for all silverhalide papers, the tone effect being clearer on silver chloride paperthan on silver bromide paperv The intensity of the 'desired tone effectcan be adjusted precisely with the concentration of the pyridinecompound in the developer solution. Very weak tone effects can beachieved with a concentration of 0.01 percent of toning agent while aconcentration of 1.0 percent gives extremely strong tone effects. Thepyridine compounds should preferably be present in the developersolution in an amount of from 0.05 to 0.3 percent. The concentration ofdeveloper and super additive, if any, is entirely conventional.

The following examples illustrate developer solutions in accordance withthe invention.

EXAMPLE 1 A toning'developer was made up according to the followingformulation:

1.5 g sodium sulfite,

2.3 g sodium carbonate.

0.06g. potassium bromide.

0.4 g. hydroquinonc.

0.02 g. phenidon (l l g Z-hydroxyelhylamino-S-aminopyridine q. I00 ml.distilled water Using this developer solution silver chloride paperwhich had been exposedfor 20 seconds with a neutral wedge filer, wasdeveloped .for 1% minutes, fixed and then washed. A neutral-brown-tonedsilver print was obtained.

In a comparative experiment, the pyridine derivative was replaced by 0.1g. of Metol. A silver chloride paper exposed and developed therein underthe same conditions as previously gave an untoned neutral-black silverprint.

EXAMPLE 2 A developer solution was made up as in example 1 but using0.06 g. of 2'-N-methylamino-5-aminopyridine in place of the 2- 'hydroxyethylamino-5amino pyridine.

A silver chloride paper exposed and developed therewith producedaclearly reddish-brown-toned silver print.

EXAMPLE 3 A developer solution was made up as in example 1 but using 0.4g. of 2,6dimethoxy-3-aminopyridine as the pyridine addirive. A silverchloride paper exposed and developed with this developergave anolive-brown-toned silver print.

EXAMPLE 4 A developer solution was made up as follows:

L3 sodium sulfite 19 g. sodium carbonate.

0.04 g. potassium bromide.

0.35 g. hydroquinone,

0.] g. p-methylaminophenol 0.! g. 2,3-diamino-o-methoxypyridine q.s. ml.distilled water Using this developer solution an exposed silver chloridepaper was developed as in example 1. The result was a strongneutral-brown-toned silver print.

EXAMPLE 5 A developer solution was made up as follows:

1.5 g. sodium sulflte 2.2 g. sodium carbonatev 0.05 g potassium bromide,0.4 g. hydroquinone,

O.l g. p-methylaminophenol, 0.02 g. phenidon 0.] g. 3,4-diaminopyridineq.s. 100 ml. distilled water.

Using this developer solution an exposed silver bromide paper wasdeveloped for 2 minutes, washed and then fixed. A yellowish-brown-tonedsilver print resulted.

We claim:

1. In an alkaline photographic developer solution containinghydroquinone as the developer the improvement comprising a toningadditive in an amount of from 0.0l-l.0 percent, said additive beingselected from pyridine compounds of the formula Rl R4 R1 and X -N X Y

2. An alkaline photographic developer solution as claimed in claim 1,wherein the amount of toning additive is 0.05-0.3 percent.
 3. Analkaline photographic developer solution as claimed in claim 1, whereinthe toning additive is selected from:2-hydroxyethylamino-5-aminopyridine 3,4-diaminopyridine2-dimethylamino-5-aminopyridine 2,6-dimethoxy-3-aminopyridine2-N-methylamino-5-aminopyridine, and 2,3-diamino-6-methoxypyridine.